I. Field of the Invention
The present invention relates generally to internal combustion engines and, more particularly, to precombustion chambers for internal combustion engines.
II. Description of the Prior Art
Although the present invention is adapted for use with various kinds of internal combustion engines having either a fixed piston or a two-part variable compression ratio (VCR) piston, particular advantage is realized by utilizing the invention in cooperation with a variable compression ratio piston similar to the type disclosed in U.S. Pat. No. 3,303,831 to Clarence A. Sherman, issued Feb. 14, 1967.
Precombustion chambers are provided for delivering an ignited fuel mixture to the main combustion chamber to aid in combustion. It has been found that optimum performance may be obtained in the operation of internal combustion engines when the volume of the precombustion chamber is maintained at some predetermined ratio of the volume of the main combustion chamber.
If a VCR piston is employed in an internal combustion engine, the volume of the main combustion chamber constantly varies throughout the operation as there is relative movement between the two parts which make up the VCR piston, and, thus, there will be a constant, incremental change in the volume of the main combustion chamber. Since there is a change in the volume of the main combustion chamber, the use of conventional precombustion chambers with a VCR piston is not favored as the aforementioned optimum proportion of the volume of the precombustion chamber to the main combustion chamber cannot be maintained as the volume of the main combustion chamber is variable while the volume of the precombustion chamber is constant.
It is therefore desirable to provide an internal combustion engine employing a VCR piston with a precombustion chamber, the volume of which is changed to maintain a predetermined constant volume ratio between its volume and the changing volume of the main combustion chamber.